No description available.

ABC drug transporter, MDR1, is a drug flippase that moves a variety of hydrophobic molecules from the inner to the outer leaflet of the plasma membrane. We have previously reported that MDR1 can function as a glycolipid flippase, being one of the mechanisms responsible for the translocation of glucosylceramide into the Golgi for neutral, but not acidic, glycosphingolipids (GSLs) synthesis. The interplay between GSLs and MDR1 could provide a whole new spectrum of innovative therapeutic options. We found that cell surface MDR1 partially co-localized with globotriaosyl ceramide (Gb3) in MDR1 transfected cells. Inhibition of GSL biosynthesis results in the loss of drug resistance and of cell surface MDR1. We speculated that an association of MDR1 and cell surface GSLs, in particular Gb3, may be functional at the cell surface, as MDR1 partitions into plasma membrane lipid rafts regulating MDR1 function. We therefore tested adamantyl Gb3 (adaGb3), a water soluble analog of Gb3, on MDR1 functions. AdaGb3 was able to inhibit MDR1-mediated rhodamine 123 drug efflux from MDR1 expressing cells, like cyclosporin A (CsA), a classical MDR1 inhibitor. AdaGb3 was also able to reverse vinblastine drug resistance in cell culture, whereas adamantyl galactosylceramide had no effect on drug resistance. The strong MDR1 reversal effects of adaGb3, as well as its favourable in vivo features make it a possible choice for inhibition of MDR1 to increase bioavailability of drugs across the intestinal epithelium (De Rosa et al., 2008). Thus, specific GSL analogs provide a new approach to MDR reversal. We have previously shown that MDR1 inhibitor CsA depletes Fabry cell lines of Gb3, the characteristic GSL accumulated in this disease, by preventing its de novo synthesis, and can also deplete Gaucher lymphoid cell lines of accumulated GlcCer (Mattocks et al., 2006). Liver and heart sections of Fabry mice treated with third generation MDR1 inhibitors showed significantly less Gb3 than liver and heart sections of untreated Fabry mice. Thus, MDR1 inhibition offers a potential alternative therapeutic approach not only for Fabry disease given the extraordinary cost of conventional enzyme replacement therapy, but also for other neutral GSL storage diseases, such as Gaucher disease.

ABC drug transporter, MDR1, is a drug flippase that moves a variety of hydrophobic molecules from the inner to the outer leaflet of the plasma membrane. We have previously reported that MDR1 can function as a glycolipid flippase, being one of the mechanisms responsible for the translocation of glucosylceramide into the Golgi for neutral, but not acidic, glycosphingolipids (GSLs) synthesis. The interplay between GSLs and MDR1 could provide a whole new spectrum of innovative therapeutic options. We found that cell surface MDR1 partially co-localized with globotriaosyl ceramide (Gb3) in MDR1 transfected cells. Inhibition of GSL biosynthesis results in the loss of drug resistance and of cell surface MDR1. We speculated that an association of MDR1 and cell surface GSLs, in particular Gb3, may be functional at the cell surface, as MDR1 partitions into plasma membrane lipid rafts regulating MDR1 function. We therefore tested adamantyl Gb3 (adaGb3), a water soluble analog of Gb3, on MDR1 functions. AdaGb3 was able to inhibit MDR1-mediated rhodamine 123 drug efflux from MDR1 expressing cells, like cyclosporin A (CsA), a classical MDR1 inhibitor. AdaGb3 was also able to reverse vinblastine drug resistance in cell culture, whereas adamantyl galactosylceramide had no effect on drug resistance. The strong MDR1 reversal effects of adaGb3, as well as its favourable in vivo features make it a possible choice for inhibition of MDR1 to increase bioavailability of drugs across the intestinal epithelium (De Rosa et al., 2008). Thus, specific GSL analogs provide a new approach to MDR reversal. We have previously shown that MDR1 inhibitor CsA depletes Fabry cell lines of Gb3, the characteristic GSL accumulated in this disease, by preventing its de novo synthesis, and can also deplete Gaucher lymphoid cell lines of accumulated GlcCer (Mattocks et al., 2006). Liver and heart sections of Fabry mice treated with third generation MDR1 inhibitors showed significantly less Gb3 than liver and heart sections of untreated Fabry mice. Thus, MDR1 inhibition offers a potential alternative therapeutic approach not only for Fabry disease given the extraordinary cost of conventional enzyme replacement therapy, but also for other neutral GSL storage diseases, such as Gaucher disease.

Dizertační práce pojednává o studiu, syntéze a chemické derivatizaci molekul spadajících do skupiny organických vysoce výkonných pigmentů a jejich potenciálním uplatnění v oblastech organické elektroniky. Teoretická část práce je zaměřena na nejnovější trendy v dané oblasti, a to jak z aplikačního potenciálu konkrétních derivátů, tak z pohledu syntetických možností a jejich strukturálních derivatizací. V experimentální části je pak podrobně popsána příprava pestré škály intermediátů a výsledných produktů, zahrnujících deriváty diketopyrrolopyrrolů (DPP), benzodifuranonu (BDF), epindolidionu (EP), naphthyridinedionu (NTD) a polymeru na bázi thiofenu (PT). Celkově bylo nasyntetizováno 103 molekul, přičemž 49 tvořily výsledné produkty, z nichž 27 bylo zcela nových, dosud nepublikovaných. Hlavním motivem derivatizace molekul pigmentů je zde inkorporace derivátů adamantanu do finálních struktur. V další části práce jsou blíže diskutovány jednotlivé chemické modifikace vedoucí k výsledným produktům. Na sérii N,N'-; N,O'- a O,O'-substituovaných derivátů DPP je popsána komplexní studie vlivu charakteru alkylových řetězců a také pozice jejich navázání v molekule DPP, a to nejen na selektivitu reakce, ale rovněž na optické i termické vlastnosti syntetizovaných produktů.

Three advanced methodologies for the preparation of extremely sterically hindered tertiary alkyl amines have been developed. The syntheses of 28 novel tertiary alkylamines that accommodate unusual steric hindrance are detailed. The electrophilic amination of alkyl Grignard reagents with N-chlorodialkylamines, in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) as a key additive, gives a variety of unprecedentedly sterically hindered tertiary alkylamines in good yields. Alternative strategy to 1-adamantyl-substituted (1-Ad) sterically hindered tertiary amines, which involved instead an SN1 reaction between 1-Ad cation with various secondary amines, is described. A complementary strategy to 1-Ad-based sterically hindered tertiary amines, which involves an iminium salt intermediate, is also reported. Salient features of the three protocols that are detailed here include unusual tolerance of steric hindrance, mild reaction conditions employed, ease of product isolation-purification, and absence of catalysts/transition metals. The molecular structures of two faithful examples of extremely sterically hindered tertiary alkylamines were determined by single crystal X-ray diffraction, and the height “h” of nitrogen pyramid of these compounds were measured. The NMR spectra show a restriction in rotation at room temperature among many hindered tertiary amines, and some of them exhibit two complete sets of peaks for two non-equivalent rotamers at room temperature. 15N NMR has been applied to study the structural changes in highly sterically hindered tertiary amines. Most of these compounds have been shown to undergo Hofmann type elimination reaction upon thermolysis at 100 degree in inert solvents, like toluene. / In der vorliegenden Arbeit wurden drei Methoden zur Synthese von tertitären Aminen mit extremer sterischer Hinderung entwickelt und zur Synthese von 28 neuen tertiären Alkylaminen mit entsprechender sterischer Hinderung angewendet. Die elektrophile Aminierung von Grignard-Reagenzien mit N-Chlordialkylaminen, unter Zusatz von N,N,N′,N′-Tetramethylethylendiamin (TMEDA) als Schlüsselkomponente, ermöglicht einen einfachen Zugang zu einer Vielzahl von tertiären Aminen mit extremer sterischer Hinderung mit guten Ausbeuten. Eine alternative Synthesestrategie unter SN1-Bedingungen führt zu sterisch-gehinderten 1-Adamantyl-substituierten (1-Ad) tertiären Aminen durch die Reaktion eines 1-Ad-Kations mit unterschiedlichen sterisch-gehinderten sekundären Aminen. Angelehnt an die zuvor beschriebene Reaktion können auch sterisch gehinderte Imine über eine Iminium-Salz-Zwischenstufe zu sterisch-gehinderten 1-Ad-substituierten tertiären Aminen umgesetzt werden. Auch in diesen Fall zeichnet sich die Reaktion durch eine bemerkenswerte Toleranz gegenüber sterischer Hinderung, milden Reaktionsbedingungen, leichte Produktisolierbarkeit und die Abwesenheit von Übergangsmetallkatalysatoren aus. Die molekulare Struktur zweier repräsentativer tertiärer Alkylamine mit extremer sterischer Hinderung wurde mittels Röntgeneinkristallstrukturanalyse untersucht und die Höhe “h” ihrer Stickstoff-Pyramide bestimmt. Die NMR-Spektren zeigen bei RT eine Einschränkung der freien Rotation um die N-C-Bindungsachse, teilweise führt dies zu vollständig getrennten Signalsätzen für die einzelnen Rotamere. 15N-NMR-Spektroskopie wurde ebenfalls zur Untersuchung von Strukturveränderungen genutzt. In inerten Lösungsmitteln, wie Toluol, zeigen die Verbindungen bei 100 °C in den meisten Fällen eine Hofmann-Eliminierung.